For some Olympic athletes, a gold medal can be a golden goose, yielding millions of dollars in advertising contracts and spokesperson gigs. While not all winning athletes will get offered such profitable jobs, ones who do should think carefully before putting their face and name on a brand.

“Time is of the essence. Athletes who have just won the gold need to move quickly if they want to land a gig with a major brand,” says Chris Cakebread, professor of advertising at the College of Communication at Boston University.

He explains American viewers have “short memories,” and that athletes should embrace their fame quickly before football season or other sports capture their attention. Even though millions of viewers tuned in for the Olympics, it doesn’t mean they will remember the athletes’ face on a Wheaties box in three months.

“Athletes should try and strike endorsement deals with national advertisers now,” Cakebread recommends. “They need to look for companies that want to offer them a four-year long contract that will take them through to the next Olympics.”

And while time is of the essence, Olympians should review every advertising and sponsorship contract closely to make sure an offer has long-term viability.

Check out the Olympic athletes making big money from sponsorships

“It’s one thing to get your picture on the side of a box of cereal, but when all the boxes sell off the shelves, what are you left with?” he says. “You have to look for a brand that’s going to stick with you for four years, not just slap your face on a package.”

Forming a long-term relationship with a brand will certainly yield more visibility for the athlete over time, but it also yields more money. Cakebread says that it’s reasonable to assume a long-term contract could run into the millions.

Not every athlete will enjoy the fame and business opportunities that 19-medaler Michael Phelps has experienced, but even just one gold medal could land a six-figure contract, according to Cakebread.

“Big brands like Coke, McDonalds, Subway, Procter and Gamble and Visa have historically had the money to pay for the athletes they want and have integrated those athletes into their brand.”

However, a gold medal doesn’t guarantee offers.

“Not all Olympians are flooded with endorsement offers,” says Jason Maloni, senior vice president and head of sports and entertainment at the Levick agency. “In fact, only the very cream of the crop have that dilemma of choosing between Coke or Pepsi.”

Those lucky enough to get a deal should do their due diligence. Maloni advises staying away from startups and .coms that have only been around for a couple months, and to pick a brand whose customers they identify with.

“If my fan base is young kids, then a cereal company could be a great fit. If I am a female swimmer, then my audience might respond well to my endorsing ladies fitness apparel,” says Maloni.

As for knowing when to turn down an offer, John McCardell, a Merrill Lynch wealth advisor based in Columbia, S.C., says that it can be a tough decision.

“Sometimes these young athletes are torn between cashing in on their success or going to college. They are extremely young and the reality is they might never be able to make this kind of money again,” says McCardell. “By the same token, if you don’t get a college degree, you may never be able to earn what you’re worth.”

Athletes who turn down an offer also take the chance of losing a revenue stream if they get hurt and can no longer compete, says McCardell. “Most young athletes think they are invincible. They think they will never blow their knee out or tear their rotator cuff, and we all know that is not the truth.”

For athletes who have decided to accept an offer, McCardell cautions that bigger is not always better.

“If you simply take the deal that will pay the most, then you’ll probably be shut off from opportunities to work with possible competitors,” he says. “Nike might offer you the most money, but they will want all your rights. You might actually be able to earn more if you struck a deal with two smaller apparel groups that were willing to work with you together.”

Andre Mika, executive vice president of marketing agency TBA Global, says that athletes should keep in mind that “there is a big difference between stardom and obscurity,” and that winning alone isn’t enough anymore.

“It’s a different day. If you win, you’ve also got to have a story to tell and a winning smile,” says Mika. “The athletes are looking for money because they’ve just spent the last 10 to 20 years of their lives living on granola bars dedicated to their craft, but they need to realize that the companies are looking for the story, for the angle.”

But no matter the beginning “angle,” Michael Stone, CEO of Beanstalk Licensing, says that Olympians can “keep the fame alive” if they work at it.

“Unlike professional sports, people only see Olympians once every four years,” says Stone. “An athlete who is doing this correctly has to like the company and the product they are endorsing, and that positive energy is going to come through.”

In the event that a deal comes to an end, Stone says athletes should look for companies that are doing “creative things.”

Cakebread adds that when in doubt, athletes should seek companies that are “innovative.”

“The person who has the medal needs to project their personality online, on video, on social media, everywhere,” Cakebread says.

“No matter what the brand is, if you come across as positive, fun, and skilled socially, brands will see you as someone they like.”